Embodiments of the present invention relate to an apparatus and method for detecting surface shear force on a display device.
Display devices have become increasingly popular, and are widely used, such as in cell phones, computer monitors, televisions, tablets, etc. These display devices may be any type of display, including an organic light emitting device (OLED) display, a liquid crystal display (LCD), etc. In particular, display devices including optical sensors have been developed, for example, to detect a user's interaction with the display device (e.g., an interaction with the display device via the user's finger or via use of a stylus).
However, although display devices with integrated optical sensors are able to detect a position of a user interaction (e.g., a user's touch), display devices have been limited in the ability to detect force of a touch interaction by the user. In particular, display devices are largely unable to detect a shear force (or shearing force) exerted by a user upon the display device. An example of a shear force interaction with a display device could be when a user applies downward pressure with the user's finger at a point on the display device and, while maintaining the position and the downward force of the finger, applies a horizontal force in any direction along the surface of the display device. In cases in which the horizontal (shear) force is less than that of the frictional force, the finger will not move, which would be an isometric gesture or isometric shear force. When the horizontal (shear) force exceeds the frictional force, there is a shear force and movement, such as a hard drag.
A display device capable of sensing a user's shear force upon the device may expand the breadth of interaction between a user and the display.